海底构造运动的指示物--多金属结核中的CaCO3/Fe2O3和MgCO3/Fe2O3比值

研究了中太平洋3个多金属结核中共5个侧面CaCO3/Fe2O3和MgCO3/Fe2O3比值的深度分布。根据CaCO3的热力学性质，我们认为结核中的CaCO3/Fe2O3比值与沉积物中的CaCO3保存量类似，与古水深之间存在着负相关关系。结核中由表及里，CaCO3/Fe2O3比值逐渐增大，说明结核所处海域，即中太平洋海盆的水深逐渐增大，这在一定程度上也反映了中太平洋海盆的下降，因而结核中的CaCO3/Fe2O3比值也许可以作为海底构造运动的指示物。而MgCO3/Fe2O3比值与其有着良好的一生，说明其与CaCO3/Fe2O3比值一样，也可以作为海底构造运动的指示物。

The Proxy of Seabed Tectonic Process: CaCO3/Fe2O3 and MgCO3/Fe2O3 Ratios in Polymetallic Nodules

CaCO 3/Fe 2O 3 and MgCO 3/Fe 2O 3 ratios' depth profiles of 5 sides in 3 polymetallic nodules from central Pacific Ocean were studied. Basing on the thermodynamics of CaCO 3, we find that the CaCO 3/Fe 2O 3 ratios in nodules, like the preservation of CaCO 3 in the sediment, show the negative correlation with paleo-depth of the ocean. The inward increase of CaCO 3/Fe 2O 3 ratios in nodules reflects the gradually increasing of depth of central Pacific Ocean basin, where these nodules locating. To a certain extent, it also reflects the general basin-sinking history of the central Pacific Ocean. We think the CaCO 3/Fe 2O 3 ratios in nodules may be used as the proxy of seabed tectonic processes. The MgCO 3/Fe 2O 3 ratios in nodules have the same trend as the CaCO 3/Fe 2O 3 ratios in nodules, i.e., the inward increasing. It may reflects the MgCO 3/Fe 2O 3 ratios in nodules can be used as the proxy of seabed tectonic processes too.